From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oa1-f78.google.com (mail-oa1-f78.google.com [209.85.160.78]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 74710395DA5 for ; Wed, 25 Mar 2026 10:43:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.78 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774435407; cv=none; b=lYSQL2Qr8KX7VbqjDfCJFcWcwY2d62Aoy5Pt4HY1+m/+7RInwDpFfEnueU+HBuUjA5YZdiNG2r4qNjslTCgzZiaFTIq+ZGg5fEtDlP7hQCEA7CEnAZuRGfysSuxtueQ5Fa4BBda7YYzjc8XVjbSaikZwxzo8xnYWYrN+yHt+29c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774435407; c=relaxed/simple; bh=2rqILl+4N509h5OcHN30omO6Y2zeTmhJoGC+vC6Kvoc=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=Myw0KD/mVThgHy0V7MPNiH4i7iybZj5nSDEB7zCRj603c+elUtD5fTnBc62MlfVK982dkoTus4T0v5dnInLYLBJdIGTw0NZ4LLWrSa02xQ6QV6jX9TxKbM7S+YLukjh9YRAowMHSMqdmjmYzaFLzLpZfXxz6BT4OyU0ZQIbcd4Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.160.78 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oa1-f78.google.com with SMTP id 586e51a60fabf-4171d16aad4so36869386fac.3 for ; Wed, 25 Mar 2026 03:43:26 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1774435405; x=1775040205; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=sth+Yx3Anp5voHgHzU56hbsx1ZXp3cay5o4gpG4EVEo=; b=p6y/E1Nldq5ac11NSZjwSLyfWFoRLNExxziH5a1h6hqjy6UDyosgIkxQYDcpX7gjSW ijmkZ31nOWdJgqJoJBCCxUJcsMJ9zU2jQurTrossJTGl7YuYSOlnAwhUh4QyAequpPHi eUfSq3XqZiWtMpxCji+rhpb8K/b21rYJqIg3FA7Mtq3gAnEirhclhUbojL3RDLJ82Did dUsFchhWvlegi1EiPHltQ0CSSPwga8u9AWIPeQkpg2sXfsGl9d9OkB8DgNlFczMFMuBU 8zF08IVyKAEdcPC9Xr2RsY+4q4M6JWpMKSAKXWIHLARVI+7U3tcMtxQZFfrBAyIO+RI1 A+Mw== X-Forwarded-Encrypted: i=1; AJvYcCViae8J9z2Vwtb1iT1uVQto0Ev9GZdQwQ1XrQbnONoeyZBX9DsbX0ArWwKcEdpL5nrYwjzoLtY=@vger.kernel.org X-Gm-Message-State: AOJu0Ywky9J2LPrmpAhNgZd/xw+dNkDeGSUE49HrNjCloNmJIJWmqFvI h2r6s6gS1LnpJ09GuoKluXJthnhGfDF5zTq4E4Vwnsa8mVR8pEydTxyBm+9Hi0AG+QXFPUqm5uz yjuDS+ptH4FYd7u5F14ES7mxRJJFNs9ByzfW6+lc1rrjbDSLZxTgUXB1rEEo= Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:1625:b0:67d:e70f:a1f with SMTP id 006d021491bc7-67dff4784fdmr1706591eaf.32.1774435405461; Wed, 25 Mar 2026 03:43:25 -0700 (PDT) Date: Wed, 25 Mar 2026 03:43:25 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69c3bc4d.a70a0220.234938.004e.GAE@google.com> Subject: [syzbot] [netfilter?] KCSAN: data-race in hash_ip4_add / hash_ip4_head From: syzbot To: coreteam@netfilter.org, davem@davemloft.net, edumazet@google.com, fw@strlen.de, horms@kernel.org, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, pabeni@redhat.com, pablo@netfilter.org, phil@nwl.cc, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 24f9515de877 Merge tag 'for-linus' of git://git.kernel.org.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=149f16da580000 kernel config: https://syzkaller.appspot.com/x/.config?x=3a78dd265deac3a9 dashboard link: https://syzkaller.appspot.com/bug?extid=1da17e4b41d795df059e compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/1bb1f4a7b1f6/disk-24f9515d.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/6d7e15112efa/vmlinux-24f9515d.xz kernel image: https://storage.googleapis.com/syzbot-assets/ffad41df862f/bzImage-24f9515d.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+1da17e4b41d795df059e@syzkaller.appspotmail.com ================================================================== BUG: KCSAN: data-race in hash_ip4_add / hash_ip4_head read-write to 0xffff88810e478c19 of 1 bytes by task 6489 on cpu 1: hash_ip4_add+0x703/0xf60 net/netfilter/ipset/ip_set_hash_gen.h:965 hash_ip4_uadt+0x452/0x500 net/netfilter/ipset/ip_set_hash_ip.c:160 call_ad+0x231/0x640 net/netfilter/ipset/ip_set_core.c:1751 ip_set_ad+0x5c0/0x690 net/netfilter/ipset/ip_set_core.c:1841 ip_set_uadd+0x41/0x50 net/netfilter/ipset/ip_set_core.c:1864 nfnetlink_rcv_msg+0x509/0x5d0 net/netfilter/nfnetlink.c:302 netlink_rcv_skb+0x123/0x220 net/netlink/af_netlink.c:2550 nfnetlink_rcv+0x167/0x1720 net/netfilter/nfnetlink.c:669 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x5c0/0x690 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x5c8/0x6f0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0x563/0x5b0 net/socket.c:2592 ___sys_sendmsg+0x195/0x1e0 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0xd4/0x160 net/socket.c:2681 x64_sys_call+0x194c/0x3020 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffff88810e478c19 of 1 bytes by task 6498 on cpu 0: hash_ip4_ext_size net/netfilter/ipset/ip_set_hash_gen.h:823 [inline] hash_ip4_head+0x283/0x950 net/netfilter/ipset/ip_set_hash_gen.h:1275 ip_set_dump_do+0xa34/0xb00 net/netfilter/ipset/ip_set_core.c:1651 netlink_dump+0x455/0x8a0 net/netlink/af_netlink.c:2325 netlink_recvmsg+0x420/0x550 net/netlink/af_netlink.c:1976 sock_recvmsg_nosec net/socket.c:1078 [inline] sock_recvmsg+0xf5/0x120 net/socket.c:1100 ____sys_recvmsg+0xf5/0x280 net/socket.c:2812 ___sys_recvmsg+0x11f/0x3b0 net/socket.c:2854 __sys_recvmsg net/socket.c:2887 [inline] __do_sys_recvmsg net/socket.c:2893 [inline] __se_sys_recvmsg net/socket.c:2890 [inline] __x64_sys_recvmsg+0xd1/0x160 net/socket.c:2890 x64_sys_call+0x2b1a/0x3020 arch/x86/include/generated/asm/syscalls_64.h:48 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0x01 -> 0x02 Reported by Kernel Concurrency Sanitizer on: CPU: 0 UID: 0 PID: 6498 Comm: syz.4.620 Tainted: G W syzkaller #0 PREEMPT(full) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 ================================================================== --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup